Question

1) Identify whether entropy increases, decreases, or remains unchanged during each of the following processes. a) Freezing liquid water b) Dissolving sodium chloride crystals into liquid water c) Expanding argon gas isothermally from 2 bar to 1 bar d) Chilling a steel ball bearing from 100 C to 25 oC e) Crystallizing a protein from an aqueous solution _- f) Heat shrink tubing shrinks (2) For each of the following processes predict qualitatively the sign for the change in entropy a) 12(g)-12(s) b) N2(8)-N20) c) CH30H(8) 3/2 02(8)CO2(2 H200) d) 2 SO3()2 02(8) 2 SO(g) (3) The complete combustion of 1-butanol, for which the data below for standard molar entropies at 298.15 K are available: (Gn J/mol-K) 225.7 Determine Asn (in I/mol-K) for this reaction. 205.2 213.8 70.0

Answer 1

Entropy is the Measurement of Randomness in the 'molécules Ha state of matter. D As Eu soled state the molecules are well defined and have proper position , Thus Randomness is dess. Iless entropy. o As in liquid state the molecules are not well packed . Remdomness more. I more entopy thein solids D bases are not well defined · Thees (mgrimum entropy YA obert bouched -> lentropy indeels © @ change is liquid - Soled (entropy decrease] 2. NaCº Alace 4 cºss J From I mole of solid to 2 mele of liquid. Centropy increased) © Expansion of gas from 2bar to Ibar; Voleme is increased. Thues more Randomness ( exhefs eval) @ cooling from 100% to 25. At high Temp., molecules are in high speed motion. The chave high Randombers, atillow Hemp), molecular motion decreases, Randomness deeleased. sentropy decreases)

@ Crystallizing a protein; Means we are arranging the molecules in a Precise Smecture Centropy decreasel) Meat I shrinks) Tubing shrinks - Wolume decreases. (entropy decreases) ® gas to solid change. entropy decrease. Tosa-me, @ NO NZD gas to liquid change more Randomness to lers Randomness Thus entropy decreases → as = -ue] © ICH OH gs +692 g) - Cag) +250 les 1 tsp mi a la mole gas. ] 11 mole gas less Randomness. more Rendom ness Thus The natue of entropy decreases. IAS > -ue] @ @sez 9) ► 20, 4)+@50 ) JA S= the 2 mole Ymdes less Random hers more randonners 2 1 2 3

@ The ginen Reaction is ; CACCH,) ON 16% -> 412) cgj +5 MOCJ 225.7 205.2 213.8 70.0 AS Reaction can be calcedated by a Espardenet Eskesetant. I asken = {59-ESR | Espo sum of entropies of Product Esgo sum of entropies of Reactant Asa xn = (4x Socos + G + SHO) -( 5° buitenol +685%) = (4x 213.8 + 5x 70.0) - ( 225.7 + 6x205.2 +(855.2 + 350 ) - ( 225.7 + 1231.2) - ( 1205.2) - ( 1456.9) Inshen 2 -251.7 J/mol-k | olk Hi Ans. 525167)